The caste system is also known as

varna
aryan

janapada

jana

It's also called VARNA

Explanation:

Varna is a means "colour, race, tribe, species, kind, sort, nature, character, quality, property" of an object or people in some Vedic and medieval texts.

answer is b.

  it is always the best policy to have good communication and good relations between individuals and, specially, between leaders of the countries. for this purpose, among others, there is a common place, the united nations, where the representants can present his and learn about the other country's policies.

the russian revolution of 1917 involved the collapse of an empire under tsar nicholas ii and the rise of marxian socialism under lenin and his bolsheviks.